Rafael Benitez will leave Newcastle when his contract expires, the club confirmed on Monday.
The former Real Madrid and Liverpool manager has thrived on Tyneside since his appointment in 2016.
He could not help the Magpies avoid relegation from the Premier League that season, with the club already in trouble, but he earned them promotion back to the top flight at the first attempt in 2017.
His subsequent successes in keeping Newcastle in the top tier on a restricted budget had endeared him to the Geordie faithful.
But the fans' greatest fears were confirmed in a statement ahead of the final day of his contract on June 30.
The club announced in a statement: "It is with disappointment that we announce manager Rafael Benítez will leave Newcastle United upon the expiry of his contract on 30th June 2019.
"We have worked hard to extend Rafa's contract over a significant period of time, however it has not been - and will not be - possible to reach an agreement with Rafa and his representatives."
The Premier League club added that Benitez's assistants Paco de Míguel Moreno, Antonio Gómez Pérez and Mikel Antia will also leave.
The statement continued: "We would like to thank Rafa and his coaching team for their efforts over the last three years and their significant contribution to what has been collectively achieved.
"We would also like to thank our supporters, players and staff for their patience during a period of uncertainty.
"The process to appoint a successor will now begin."
File photo dated 12-03-2016 of Newcastle United's new manager Rafael Benitez.
File photo dated 15-12-2018 of Newcastle United manager Rafael Benitez.
File photo dated 05-12-2018 of Newcastle United manager Rafael Benitez.
Newcastle United manager Rafael Benitez
Newcastle United's Federico Fernandez with family and Newcastle United manager Rafael Benitez after the final whistle
Newcastle United manager Rafael Benitez speaks with Newcastle United's Matt Ritchie
Newcastle United manager Rafael Benitez (left) and assistant manager Francisco De Miguel Moreno prior to the Premier League match at St James' Park, Newcastle. PRESS ASSOCIATION Photo. Picture date: Saturday December 9, 2017. See PA story SOCCER Newcastle. Photo credit should read: Owen Humphreys/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.
Napoli's Spanish manager Rafa Benitez (L) salutes his Slovak midfielder Marek Hamsik after his substitution during their Italian Super Cup football match against Juventus FC - which is contested between the 2014 Serie A Champions (Juventus) and the 2014 Coppa Italia Holders (Napoli) - at the Sheikh Jassim Bin Hamad Stadium, in the Qatari capital, Doha on December 22, 2014. AFP PHOTO / AL-WATAN DOHA / KARIM JAAFAR
==QATAR OUT== (Photo credit should read KARIM JAAFAR/AFP/Getty Images)
(GERMANY OUT) FUSSBALL INTERNATIONAL Coppa Italia Finale 2013/2014
AC Florenz - SSC Neapel
JUBEL, Sieger SSC Neapel; Goekhan Inler (li) und Trainer Rafael Benitez (re) (Photo by Pressefoto Ulmer\ullstein bild via Getty Images)
Chelsea's interim manager Rafael Benitez (right) and Everton manager David Moyes (left) both gesture and shout instructions on the touchline (Photo by John Walton - EMPICS/PA Images via Getty Images)
LIVERPOOL, ENGLAND - APRIL 15: (THE SUN OUT) (NO SALES) In this handout image provided by Liverpool FC, Former Manager Rafael Benitez of Liverpool FC wipes a tear from his eye during the Hillsborough memorial service at Anfield on April 15, 2011 in Liverpool, England. The Hillsborough Independent Panel was set up over a year ago by then Home Secretary Alan Johnson to gather and scrutinise information relating to the tragedy, including previously undisclosed documents, in an attempt to provide maximum disclosure of events that took on April 15, 1989. (Photo by Andrew Powell/Liverpool FC via Getty Images)
Inter Milan's coach Rafael Benitez attends a training session at Zayed Sports City in the Emirati capital Abu Dhabi on December 17, 2010 on the eve of the FIFA Club World Cup final. AFP PHOTO/KARIM JAAFAR (Photo credit should read KARIM JAAFAR/AFP/Getty Images)
ABU DHABI, UNITED ARAB EMIRATES - DECEMBER 17: Diego Milito, Javier Zanetti, Maicon and Dejan Stankovic listen to Inter manager Rafael Benitez during the FC Internazionale Milano Training Session at the Armed Forces Stadium on December 17, 2010 in Abu Dhabi, United Arab Emirates. (Photo by Michael Regan - FIFA/FIFA via Getty Images)
President of Real Madrid football team, Florentino Perez gives a press conference to present Rafael Benitez as the team's new head-coach at the Santiago Bernabeu stadium in Madrid on June 3, 2015. The hiring of Rafael Benitez as Real Madrid boss today makes the Spaniard the 10th coach to serve under Florentino Perez during his two spells as the club's president between June 2000-February 2006 and since June 2009. AFP PHOTO / PIERRE-PHILIPPE MARCOU (Photo credit should read PIERRE-PHILIPPE MARCOU/AFP/Getty Images)
Rafael Benitez, Liverpool manager (Photo by Nick Potts/PA Images via Getty Images)
Liverpool manager Rafael Benitez (Photo by Barrington Coombs - EMPICS/PA Images via Getty Images)
The new head-coach of Real Madrid football team, Rafael Benitez (L) and Real Madrid's president Florentino Perez smile as they pose with the team's jersey during a press conference at the Santiago Bernabeu stadium in Madrid on June 3, 2015. The hiring of Rafael Benitez as Real Madrid boss today makes the Spaniard the 10th coach to serve under Florentino Perez during his two spells as the club's president between June 2000-February 2006 and since June 2009. AFP PHOTO / PIERRE-PHILIPPE MARCOU (Photo credit should read PIERRE-PHILIPPE MARCOU/AFP/Getty Images)
Liverpool's manager Rafael Benitez urges more effort from his team during the game against Southampton (Photo by Barrington Coombs - EMPICS/PA Images via Getty Images)
The future King of England meets the current kings of European football today, with a visit to Anfield, the home of Liverpool FC .Prince Charles and the Duchess of Cornwall chat to Liverpool captain Steven Gerrard holding the Champions league trophy during a visit to the club's Anfield ground to see a Princes Trust scheme. Also pictured are Liverpool manager Rafael Benitez (L) and chairman David Moores (R) See PA Story ROYAL Charles. PRESS ASSOCIATION PHOTO Photo credit should read Phil Noble WPA Pool/PA PA pool photo Phil Noble (Photo by Phil Noble - PA Images/PA Images via Getty Images)
Liverpool's Steven Gerrard and manager Raphael Benitez walk down the steps of the aircraft with the Champions League Trophy (Photo by Simon Bellis - EMPICS/PA Images via Getty Images)
Benitez, 59, replaced Steve McClaren in March 2016 with the club facing a dire threat of relegation.
He helped them to a six-match unbeaten streak at the end of the season, but they fell just short in a bid to avoid the drop - with 12 points collected in that time.
But they finished as Championship winners the following season, pipping Brighton to the title by one point and earning automatic promotion.
Owner Mike Ashley reportedly put the club up for sale since their re-entrance to the Premier League, restricting the Magpies' budget for transfers.
It has meant that - the £20million acquisition of Miguel Almiron aside - Benitez was left working with scraps.
The talented manager led Newcastle to a tenth-placed finish in their first season back, before a 13th-placed finish last season, despite being in the relegation zone in January.
And it seemed Ashley could not convince Benitez to remain at the club any longer, with Garry Monk, Eddie Howe and Mikel Arteta leading the favourites to replace him at Betfair.
Fans of the magpies vented their frustration and disappointment on Twitter:
Desperately disappointing. That's an understatement. An absolutely massive job now to appoint a successor that can try and unite the fans like Rafa did. Honestly I'm shocked. Still believed this morning they'd somehow find a resolution this week. #nufchttps://t.co/N1gkx70fyJ